Contour self-adaptive metal mold hot-pressing shaping processing method

Abstract

The invention belongs to the technical field of part forming hot working, and discloses a contour self-adaptive metal mold hot-pressing setting machining method which comprises the steps that a metal material with the melting point lower than the hot-pressing temperature of a part to be subjected to hot-pressing setting is selected; putting the metal material into a container, heating and melting; sinking a part to be hot-pressed into the molten metal material; filling gas into the container, and keeping the pressure; and releasing the pressure, and taking out the machined part to finish the hot-pressing shaping. A to-be-machined part is immersed in liquid metal and pressurized, and hot isostatic pressing and shaping treatment of the part are achieved; the defects that a high-precision hot-pressing die is high in design and manufacturing cost and large in pressure equipment investment are overcome, the defect that die pressing parts are sequentially machined to be low in efficiency is overcome, and the problem that hot pressing cannot be conducted on an open micropore structure due to high permeability of gas is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of hot processing of parts forming, and in particular relates to a hot pressing and shaping processing method of a contour-adaptive metal mold. Background Art

[0002] The hot pressing process involves applying heat and pressure to a part, already formed by a specific processing method, to further enhance and improve its internal structure, dimensions, and surface topography. This process typically involves molding a solid mold with fixed dimensions or performing hot isostatic pressing using high-pressure, high-temperature gas.

[0003] Due to the particularity of the part structure, the solid molds commonly used in part molding and hot pressing have disadvantages such as difficulty in design and processing, and the inability to apply pressure locally. At the same time, there are also problems such as large plastic deformation of the parts due to the movement of the mold, material extrusion, and uneven force on different parts of the parts; the high-pressure and high-temperature gas used in hot isostatic pressing has strong permeability, and hot isostatic pressing cannot be achieved for parts with open microporous structures.

[0004] The Chinese patent publication number is CN108421980A, and the name is a patent application for a hot isostatic pressing method based on additive manufacturing. The method uses layered structural materials instead of powdered materials as raw materials for hot isostatic pressing based on the concept of additive manufacturing, and realizes hot isostatic pressing of the part to be formed by using support materials and two hot isostatic pressing processes. Specifically, it includes: obtaining a three-dimensional CAD model of the part to be formed, slicing the three-dimensional CAD model of the part to be formed to obtain each slice layer and the corresponding two-dimensional contour information, selecting the preparation material of the part to be formed as the slice material, and processing the slice material according to the two-dimensional contour information to obtain all slice layers; preparing a support layer with the same thickness as the slice layer using a metal material with a lower melting point than the part to be formed, each slice layer is provided with a support layer, and the shape of the corresponding slice layer is cut out in each support layer according to the two-dimensional contour information of the corresponding slice layer, so that each support layer is exactly nested on the corresponding slice layer; each processed slice layer is placed in the cut-off part of the corresponding support layer in turn, and then the assembly is arranged according to the order of the layers of the part to be formed. The good slices are stacked in sequence to obtain a three-dimensional object to complete the preparation of raw materials for hot isostatic pressing; the corresponding package is processed according to the external contour of the three-dimensional object obtained by superposition, and the three-dimensional object is placed in the package to obtain a part blank with a package, and then the part blank with a package is placed in a heating furnace for heating, and the inside of the package is vacuumed, and then sealed and welded; the part blank with a package is subjected to the first hot isostatic pressing treatment, and the package is removed after the first hot isostatic pressing; the three-dimensional object without the package is placed in a heating furnace with a temperature between the melting point of the support material and the melting point of the forming part material for heating, and the part intermediate blank is obtained when the support material is completely melted and separated from the slice layer; the part intermediate blank is taken out and subjected to a second hot isostatic pressing treatment to obtain the required formed part. This method solves the problems of complex sheaths and internal shape-control cores that are difficult to process and remove, the complex computer simulation of the powder densification process during hot isostatic pressing that makes precise shape control difficult, and the powder particle boundaries in the workpiece that are difficult to eliminate and have low fatigue performance. However, the method of this patent application cannot solve the problems of plastic deformation of parts, material extrusion, and uneven force on different parts of the parts during the processing process. Summary of the Invention

[0005] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a contour-adaptive metal mold hot pressing and shaping processing method, which realizes hot isostatic pressing and shaping of the parts by immersing the parts to be processed in liquid metal and pressurizing them; avoids the disadvantages of high design and manufacturing costs of high-precision hot pressing molds and large investment in pressure equipment, overcomes the shortcomings of low efficiency in sequential processing of molded parts, and solves the problem that open microporous structures cannot be hot pressed due to high gas permeability.

[0006] To achieve the above object, the technical solution adopted by the present invention is: A contour adaptive metal mold hot pressing shaping processing method comprises the following steps: Select a metal material with a melting point lower than the hot pressing temperature of the part to be hot pressed and shaped; Put the metal material into a container and heat it to melt; sinking the part to be hot-pressed into the molten metal material; Fill the container with gas to maintain pressure; Release the pressure and take out the processed parts to complete the hot pressing and shaping.

[0007] Optionally, the melting point of the metal material is lower than the hot pressing temperature of the part to be hot pressed and shaped in the range of 50 to 100°C.

[0008] Optionally, when the material of the part to be hot-pressed and formed is plastic, the pressure is maintained at 20 MPa; when the material of the part to be hot-pressed and formed is metal, the pressure is maintained at 200 MPa.

[0009] Optionally, when the part to be hot pressed is sunk into the molten metal material, an auxiliary external contour dimension supporting tooling is provided outside the part to be hot pressed.

[0010] Optionally, when the part to be hot pressed is sunk into the molten metal material, an auxiliary internal contour dimension supporting tooling is provided inside the part to be hot pressed.

[0011] Optionally, during the pressure relief process, the temperature is kept constant.

[0012] Optionally, the part to be hot-pressed and formed is a machined fluoroplastic rod or a metallurgical part blank.

[0013] Optionally, the time for filling the container with gas and maintaining the pressure is 30 to 90 minutes.

[0014] Optionally, the container has a cover, and the container is a sealed container.

[0015] Optionally, when the part to be hot-pressed is sunk into the molten metal material, the temperature is maintained to be greater than the melting point of the metal material and less than the melting point of the part to be hot-pressed.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention proposes a contour-adaptive metal mold hot pressing and shaping processing method, which uses a metal with a melting point lower than the hot pressing temperature of the part to be hot pressed and shaped as the mold material. After reaching the hot pressing temperature, the liquid metal melts to surround and fill the inner and outer walls of the part to be processed, making full use of the advantage of the large surface tension of the liquid metal to automatically form a contour-adaptive metal mold. If the part to be hot pressed has a part with higher dimensional requirements, a higher-strength solid mold part is used to provide local support. The part to be hot pressed is completely immersed in the liquid metal, and pressure is applied to the liquid metal, thereby achieving hot isostatic pressing and shaping of the part.

[0017] Furthermore, the method of the present invention can meet the requirements of processing a batch of parts simultaneously with the same processing effect. After the pressure processing is completed, the liquid metal has a large heat capacity and can continuously keep the parts warm. The parts can then be removed from the liquid metal and cooled to achieve the desired heat treatment effect.

[0018] The present invention proposes a contour-adaptive metal mold hot pressing shaping processing method, which avoids the disadvantages of high design and manufacturing costs of high-precision hot pressing molds and large investment in pressure equipment, overcomes the inefficiency of sequential processing of molded parts, and solves the problem that open microporous structures cannot be hot pressed due to high gas permeability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only schematic and are used to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention. In the drawings: Figure 1 This is a schematic diagram of a hot-pressed sealed can according to an embodiment of the present invention; Figure 2 Schematic diagram of the steps of the method of the present invention; Among them, 1. The first workpiece to be hot-pressed and shaped; 2. Auxiliary internal contour dimension support tooling; 3. The second workpiece to be hot-pressed and shaped; 4. Auxiliary external contour dimension support tooling; 5. Liquid metal; 6. Hot-pressed sealed can. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0022] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0023] When an element is referred to as being "disposed on" another element, it may be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may also be an intermediate element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiments. If the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and it does not mean that the structure must be completely horizontal, but it can be slightly tilted.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures. In the description of the present invention, it should be understood that the terms "comprise" and "include" indicate the presence of the described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their combinations.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0026] The present invention will be described in detail below with reference to the accompanying drawings.

[0027] Hot isostatic pressing (HIP) is a material processing method widely used in the preparation of high-performance materials and the manufacture of key components. Through the combined effects of high temperature and high pressure, materials are densified and sintered under isotropic pressure, significantly improving their mechanical properties and corrosion resistance. The basic principle of HIP is to place powder or a product in a sealed envelope. By applying isotropic pressure and high temperature to the envelope, the powder or product within the envelope is sintered and densified. This technique effectively eliminates micropores, cracks, and segregation defects within the material, thereby improving its density and uniformity. However, existing HIP methods have the following problems: the solid molds commonly used for hot pressing and shaping parts are difficult to design and manufacture, and local pressure cannot be applied. Significant deformation due to mold movement can occur, resulting in material extrusion and uneven stress distribution across the part. Furthermore, the high-pressure, high-temperature gas used in existing HIP methods has strong permeability, making HIP impractical for parts with open microporous structures.

[0028] like Figure 2 As shown, a contour adaptive metal mold hot pressing shaping processing method of the present invention comprises the following steps: Select a metal material with a melting point lower than the hot pressing temperature of the part to be hot pressed and shaped; Put the metal material into a container and heat it to melt; sinking the part to be hot-pressed into the molten metal material; Fill the container with gas to maintain pressure; Release the pressure and take out the processed parts to complete the hot pressing and shaping.

[0029] The present invention proposes a contour-adaptive metal mold hot-pressing shaping method that uses a metal with a melting point lower than the hot-pressing temperature of the part to be hot-pressed and shaped as the mold material. Upon reaching the hot-pressing temperature, the liquid metal melts, surrounds, and fills the inner and outer walls of the part to be processed, fully utilizing the liquid metal's high surface tension to automatically form a contour-adaptive metal mold. If the part to be hot-pressed has areas with higher dimensional requirements, higher-strength solid mold pieces are used for local support. The part to be hot-pressed is completely immersed in the liquid metal, which applies pressure to the liquid metal, thereby achieving hot isostatic pressing and shaping of the part. The contour-adaptive metal mold hot-pressing shaping method proposed by the present invention avoids the drawbacks of high design and manufacturing costs of high-precision hot-pressing molds and large investment in pressure equipment, overcomes the inefficiency of sequentially processing molded parts, and solves the problem of open microporous structures being unable to be hot-pressed due to high gas permeability.

[0030] Example 1 The following combination Figure 1The specific embodiments of the present invention are further described.

[0031] like Figure 1 As shown, in this embodiment, the contour adaptive metal mold hot pressing shaping processing method includes the following steps: Step 1: Select a pure metal or alloy with a melting point lower than the hot pressing temperature of the hot-pressed part.

[0032] Step 2: Select a pressure-bearing container with a large capacity, an openable cover and the ability to withstand pressure as the sealed autoclave 6.

[0033] Step 3: Place the pure metal or alloy into a sealed autoclave 6 and heat and melt it to form liquid metal 5.

[0034] Step 4: sink the part to be hot pressed or the part to be hot pressed with a shaped support mold into the molten liquid metal 5.

[0035] Step 5: Fill the sealed autoclave 6 with gas and keep it for a period of time to complete the autoclave.

[0036] The method of the present invention can meet the requirements of processing a batch of parts at the same time, with the same processing effect. After the pressure processing is completed, the liquid metal has a large heat capacity and can continuously keep the parts warm. The parts can then be removed from the liquid metal and cooled to achieve the effect of heat treatment.

[0037] Optionally, the melting point of the pure metal or alloy having a lower melting point than the hot pressing temperature of the part to be hot pressed and formed is 50 to 100° C. lower than the melting point of the part to be hot pressed and formed.

[0038] Optionally, the part to be hot-pressed is a first workpiece 1 to be hot-pressed and shaped, and the first workpiece 1 to be hot-pressed and shaped has an auxiliary internal contour support fixture 2 therein, the auxiliary internal contour support fixture 2 being in contact with the inner wall of the first workpiece 1 to be hot-pressed and shaped. In step 4, the auxiliary internal contour support fixture 2 is supported within the first workpiece 1 to be hot-pressed and shaped, and is simultaneously submerged in the molten liquid metal 5.

[0039] Optionally, the part to be hot pressed is a second workpiece 3 to be hot pressed and shaped, and an auxiliary external contour support fixture 4 is provided on the outside of the second workpiece 3 to be hot pressed and shaped, and the auxiliary external contour support fixture 4 contacts the outer wall of the second workpiece 3 to be hot pressed and shaped. In step 4, the second workpiece 3 to be hot pressed and shaped is placed on the outside of the second workpiece 3 to be hot pressed and shaped, and is simultaneously sunk into the molten liquid metal 5.

[0040] Example 2 In this embodiment, the parts to be hot-pressed and shaped are fluoroplastic machined parts, which are hot-pressed and shaped using a contour-adaptive metal mold, thereby realizing batch hot-pressing processing without the mold.

[0041] The specific steps are: Mechanically process fluoroplastic rods into parts, forming one or more batches of multiple parts; prepare an autoclave 6, place a certain amount of low-melting-point metal in it, specifically, the low-melting-point metal is Pb-Sn alloy, and heat the autoclave 6 to melt it.

[0042] Immerse multiple fluoroplastic parts from the same batch in liquid metal 5 and seal the autoclave; Heat the autoclave to the specified temperature and then keep it warm. Fill the sealed autoclave with gas and maintain the pressure for 60 minutes. Release the pressure, open the sealed autoclave 6, take out the fluoroplastic parts and cool them down to complete the hot isostatic pressing and shaping.

[0043] The part to be hot-pressed and formed is completely immersed in the liquid metal 5. The pressure relief process maintains a constant temperature and releases pressure slowly. Alternatively, a high-temperature-resistant mechanical gripper can be used to immerse the part in the liquid metal 5 and remove it after cooling. High-temperature-resistant mechanical grippers can withstand high temperatures, ensuring long-term stable operation in harsh environments. They can quickly handle large numbers of high-temperature parts while ensuring part quality and integrity.

[0044] The present invention's contour-adaptive metal mold hot-pressing shaping method enables simultaneous processing of a batch of parts with identical results. After the press process, the liquid metal, with its large heat capacity, can continuously maintain the heat of the parts. The parts can then be removed from the liquid metal and cooled to achieve the desired heat treatment effect.

[0045] Example 3 In this embodiment, the part to be hot-pressed and shaped is a blank cast from an aluminum alloy or magnesium alloy, or a blank made from powder metallurgy parts, and hot isostatic pressing using a contour-adaptive metal mold is used to improve the internal density and mechanical properties.

[0046] The specific steps are: prepare a high-pressure autoclave, place the casting blank and the powder metallurgy part blank in it, then add an appropriate amount of low-melting-point metal, specifically, the low-melting-point metal is Pb-Sn alloy, and seal the autoclave 6.

[0047] After heating the autoclave 6 and then keeping it warm, the sealed autoclave 6 is filled with gas and the pressure is maintained for 60 minutes.

[0048] The pressure is released, and the sealed autoclave 6 is opened to remove the blank part and cool it, completing the hot isostatic pressing process. The pressure is released slowly while maintaining a constant temperature. Alternatively, the part to be hot-pressed and formed can be immersed in the liquid metal 5 using a high-temperature-resistant mechanical gripper and removed using the same gripper after cooling.

[0049] Example 4 In this embodiment, the part to be hot-pressed and shaped is plastic.

[0050] The specific steps are: prepare a high-pressure autoclave, place the casting blank and the powder metallurgy part blank in it, then add an appropriate amount of low-melting-point metal, specifically, the low-melting-point metal is Pb-Sn alloy, and seal the autoclave 6.

[0051] After heating the autoclave 6, the autoclave is kept warm, and the sealed autoclave 6 is filled with gas, and the pressure of 20 MPa is maintained for 30 minutes.

[0052] The pressure is released, and the sealed autoclave 6 is opened to remove the blank part and allow it to cool, completing the hot isostatic pressing process. The temperature is maintained constant during the pressure release process, and the pressure is released slowly. Alternatively, the part to be hot-pressed and formed is immersed in the liquid metal 5 using a high-temperature resistant mechanical gripper, and then removed from the hot-pressed and formed part after cooling using the high-temperature resistant mechanical gripper.

[0053] Example 5 In this embodiment, the part to be hot-pressed and shaped is metal.

[0054] The specific steps are: prepare a high-pressure autoclave, place the casting blank and the powder metallurgy part blank in it, then add an appropriate amount of low-melting-point metal, specifically, the low-melting-point metal is Pb-Sn alloy, and seal the autoclave 6.

[0055] After heating the autoclave 6 and then keeping it warm, the sealed autoclave 6 is filled with gas and the pressure of 200 MPa is maintained for 90 minutes.

[0056] The pressure is released, and the sealed autoclave 6 is opened to remove the blank part and allow it to cool, completing the hot isostatic pressing process. The temperature is maintained constant during the pressure release process, and the pressure is released slowly. Alternatively, the part to be hot-pressed and formed is immersed in the liquid metal 5 using a high-temperature resistant mechanical gripper, and then removed from the hot-pressed and formed part after cooling using the high-temperature resistant mechanical gripper.

[0057] The present invention proposes a contour-adaptive metal mold hot pressing shaping processing method, which avoids the disadvantages of high design and manufacturing costs of high-precision hot pressing molds and large investment in pressure equipment, overcomes the inefficiency of sequential processing of molded parts, and solves the problem that open microporous structures cannot be hot pressed due to high gas permeability, as well as the problems of part plastic deformation, material extrusion, and uneven force on various parts during the processing process.

[0058] Unless otherwise specified, the device components involved in the above embodiments are all conventional device components, and the structural settings, working modes or control modes involved are all conventional settings, working modes or control modes in the art unless otherwise specified.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limiting. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A contour adaptive metal mold hot pressing shaping processing method, characterized in that: The following steps are involved: Select a metal material with a melting point lower than the hot pressing temperature of the part to be hot pressed and shaped; Put the metal material into a container and heat it to melt; sinking the part to be hot-pressed into the molten metal material; Fill the container with gas to maintain pressure; Release the pressure and take out the processed parts to complete the hot pressing and shaping.

2. A contour adaptive metal mold hot pressing shaping processing method according to claim 1, characterized in that: The melting point of the metal material is 50 to 100° C. lower than the hot pressing temperature of the part to be hot pressed and shaped.

3. The contour adaptive metal mold hot pressing shaping processing method according to claim 1, characterized in that: When the material of the part to be hot-pressed and shaped is plastic, the pressure is maintained at 20 MPa. When the material of the part to be hot-pressed and shaped is metal, the pressure is maintained at 200 MPa.

4. The contour adaptive metal mold hot pressing shaping processing method according to claim 1, characterized in that: When the part to be hot-pressed is sunk into the molten metal material, an auxiliary external contour dimension supporting tooling is arranged outside the part to be hot-pressed.

5. The contour adaptive metal mold hot pressing shaping processing method according to claim 1, characterized in that: When the part to be hot-pressed is sunk into the molten metal material, an auxiliary internal contour dimension supporting tool is arranged inside the part to be hot-pressed.

6. The contour adaptive metal mold hot pressing shaping processing method according to claim 1, characterized in that: During the pressure relief process, keep the temperature constant.

7. The contour adaptive metal mold hot pressing shaping processing method according to claim 1, characterized in that: The parts to be hot-pressed and shaped are machined fluoroplastic rods or metallurgical parts blanks.

8. The contour adaptive metal mold hot pressing shaping processing method according to claim 1, characterized in that: The container is filled with gas and the pressure is maintained for 30 to 90 minutes.

9. The contour adaptive metal mold hot pressing shaping processing method according to claim 1, characterized in that: The container has a cover, and the container is a sealed container.

10. The contour adaptive metal mold hot pressing shaping processing method according to claim 1, characterized in that: When the part to be hot-pressed is sunk into the molten metal material, the temperature is kept higher than the melting point of the metal material and lower than the melting point of the part to be hot-pressed.

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